Specificity and Sensitivity of Radioimmunoassay for Hepatitis B Antigen

Abstract

Sera from a survey of 6,026 people were tested for hepatitis B surface antigen by using radioimmunoassay and counterelectrophoresis. Forty-eight sera (0.79%) were positive by counterelectrophoresis and 152 sera (2.52%) were positive by radioimmunoassay, using the most liberal of the recommended criteria for positivity (i.e., counts 3 standard deviations above the mean). Absorption tests performed on the 152 radioimmunoassay-positive sera showed that 10 (6.6%) were false-positive reactions to guinea pig protein, 74 (48.6%) were due to false-positive reaction(s) with other protein(s) in the test system, and 68 (44.8%) were true positives. There was a strong correlation between the degree of elevation of radioactive counts and the proportions of sera that were true positives; all 49 sera with counts >50 standard deviation units above the mean were true positives, but only 19 (18.4%) of the 103 sera with counts <50 standard deviation units were true positives. A few sera with high counts required absorption with type-specific (type D) antisera. The following conclusions were reached from this study: (i) absorption tests should be run on all radioimmunoassay-positive, counterelectrophoresis-negative sera; (ii) most (about 90%) false positives are not due to anti-guinea-pig protein reactions; and (iii) radioimmunoassay, in combination with absorption tests, yields a modest increase (about 35%) in detection of true positives over use of counterelectrophoresis alone.

Transmission of Hepatitis B Virus to Gibbons by Exposure to Human Saliva Containing Hepatitis B Surface Antigen

“…Detection of HB s Ag, anti-H'B ., and e antigen. All samples of serum and saliva were tested for HB s Ag by solid-phase radioimmunoassay (Ausria II, Abbott Laboratories, North Chicago, Ill.) without preliminary preparation [22]. Positive reactions were confirmed by~50% reduction of test serum reactivity after incubation with a human serum containing anti-Hb., Titers of antigen in serum were determined by CF tests [23], HB s Ag subtypes were detected by immunodiffusion [24], and e antigen [25] was detected in serum by immunodiffusion with serum from a Thai blood donor as antibody.…”

Epidemic Hepatitis B: A Sustained Outbreak in a Large Military Population

“…Beginning in January 1972, 12 months after the start of the epidemic, sera from newly admitted hepatitis patients and blood donors were routinely tested for hepatitis B surface antigen (HB s Ag) in the hospital laboratory using a commercially available counterelectrophoresis (CEP) system (Spectra Biological, Oxnard, CA). In the case-control study, sera were tested for HB s Ag using both CEP and radioimmunoassay (RIA) with appropriate absorption procedures (6). CEP-positive sera were subtyped for HB s Ag determinants d, y (7), w arid r (8).…”

Persistence of antibody to hepatitis B surface antigen

“…Antibody was diluted serially from 1:8 to 4,096. One-tenth milliliter each of antigen and antibody was mixed in a 75-mm glass tube and allowed to incubate for 2 h. After incubation, 0.1 ml of the mixture was transferred to an Ausria I (Abbott Laboratory) tube and tested for the presence of HB,Ag (7,9). Controls containing antigen or antibody alone and diluent were included in each test.…”